There have been numerous attempts over many decades to find an economical, practical, and safe solution to the problems presented by hauling relatively large, heavy objects, and in particular heavy objects with curved outer surfaces, such as metal coils, pipes, structures, concrete shapes, and the like. The default method of hauling such items is to chain them down to a conventional flatbed trailer, as shown for example in FIG. 1. However, this presents important practical and safety issues when hauling large, heavy objects having curved outer surfaces, because those objects tend to roll, tip over, and become dislodged, which at a minimum can damage the cargo, and can easily prove fatal to the driver or others on the road. Accordingly, specialized trailers have been designed, for instance to allow particular curved objects to nest into the trailer. See for example the following United States patents, all of which are incorporated herein by reference: U.S. Pat. No. 2,810,602 issued 1957 Oct. 22 to Abrams; U.S. Pat. No. 3,291,072 issued 1966 Dec. 13 to Cunningham; U.S. Pat. No. 3,353,506 issued 1967 Nov. 21 to Snyder; U.S. Pat. No. 3,481,627 issued 1969 Dec. 2 to Felburn; U.S. Pat. No. 3,605,638 issued 1971 Sep. 20 to James; U.S. Pat. No. 5,211,518 issued 1993 May 18 to Mimica; U.S. Pat. No. 5,343,813 issued 1994 Sep. 6 to Septer; U.S. Pat. No. 5,401,129 issued 1995 Mar. 28 to Eatinger; U.S. Pat. No. 5,425,608 issued 1995 Jun. 20 to Reitnouer; U.S. Pat. No. 5,577,619 issued 1996 Nov. 26 to Callahan; U.S. Pat. No. 5,622,116 issued 1997 Apr. 22 to Carlton; U.S. Pat. No. 6,190,100 B1 issued 2001 Feb. 20 to Mawji; U.S. Pat. No. 6,923,608 B2 issued 2005 Aug. 2 to Rediehs; and U.S. Pat. No. 7,628,418 B1 issued 2009 Dec. 8 to Holmes. These specialized trailer designs and similar complex systems may address some of the safety problems in theory, but as a practical matter such designs and systems are typically not used. Such designs have never gained acceptance over conventional flatbed trailers due to their cost, complexity, and lack of ready availability compared to the ubiquitous flatbed trailer, which already exists and is not limited to any special uses. Thus, even in view of the well-documented safety hazards, flatbed trailers and chains continue to be the primary method of hauling heavy objects with curved outer surfaces, such as metal coils, pipes, structures, concrete shapes, and the like.
Further considerations are raised when hauling one or more metal coils such as steel or aluminum, which comprise a winding of metal sheeting which is coiled for convenient bulk transport, storage, and subsequent processing. As shown in FIG. 1, such metal coils 10 are typically quite massive, and are usually hauled upright such that the curved outer diameter 13 is supported directly on the flatbed trailer 20, with chains 30 attached to the trailer 20 and running through the central open portion of the coil 10 and pressing downward with great pressure on the curved inner diameter 12 of the coil 10. The coils 10 are preferably hauled upright instead of flat-face down to facilitate loading and unloading using a forklift fork or similar device placed inside the central opening in the coil 10. Pieces of wood 15 are often wedged under the sides of the curved outer diameter 13 in an attempt to stop the coil 10 from rolling, such that the adjoining corner of the wood 15 places high pressure on the mating surface 13 of the coil 10. Due to the mass of the coil 10, this hauling system results in high pressure being applied to local portions of the metal coil 10, which is amplified as the coil 10 shifts or rocks during transport. This frequently damages the inner 12 and/or outer 13 surfaces of the coil 10, rendering a number of windings bent, scuffed, and unusable. With current manufacturing techniques, including “just-in-time” manufacturing and zero-defect quality controls, consumers of metal coils have demanded that the coils be shipped without damage of virtually any kind, so that the coils can be unloaded and set up at the last minute in a manufacturing operation, with little to no waste. Accordingly, a strong need remains for a better way of hauling relatively large, heavy objects with curved outer surfaces, that is practical and sufficiently economically feasible that it will be actually adopted by industry.
Another challenge that has arisen in connection with “just in time” and “lean” manufacturing is that end-users of metal coils are demanding that they be delivered in their final widths for subsequent manufacturing processes, which are often thinner, sometimes much thinner, than the standard widths normally shipped. For example, as shown in FIG. 2, whereas a conventional metal coil might have width W1, customers are requesting delivery of metal coils having narrower widths W2. This makes the coils 10 much more unstable and likely to tip over, increasing the dangers associated with shipment along with the likelihood of damage due to movement during shipping, including relative movement between adjacent coils that can damage the outer edges 11 of the coiled metal. A simple, relatively inexpensive, and easy-to-adopt solution is needed to address these challenges.